import std.stdio;
import core.stdc.signal;
import core.sys.posix.sys.time;

extern(C)
nothrow @nogc @system void func(int sig){
      printf("%d", sig);
}

void main(){
      signal(SIGALRM, &func);
      itimerval time;
      time.it_value.tv_sec = 0;
      time.it_value.tv_usec = 500;
      time.it_interval.tv_sec = 0;
      time.it_interval.tv_usec = 500;
      setitimer(ITIMER_REAL, &time, null);
}